main() {
  var name = '张三';
  print(name);
  name = '李四';
  print(name);
  var age = 18;
  print(age);
  var isMan = true;
  print(isMan);
  isMan = false;
  print(isMan);

  const BASE_URL = 'https://www.itcast.cn';
  print(BASE_URL);
}
